Hydrocarbon conversion



Patented Nov. 30, 1943 UNITED STATES-PATENT. OFFlCE HYDROCARBON CONVERSION ware No Drawing. Application December 18, 1942,

' Serial No. 469,473

6 Claims. (Cl. 196-52) This invention relates to aprocess for the reduction of the olefin content of a hydrocarbon fraction. More specifically, it is concerned with a process for reducing the bromine number of .a gasoline boiling range fraction to prepare a hydrocarbon fraction suitable for aviation -fuel purposes.

Cracking or reforming operations generally produce gasolines which have a high initial tane number, but which have a relatively low lead susceptibility due to their high olefin content. For this reason gasolines produced by these processes are usually unsatisfactory as aviation fuel base stocks.

We have found that a gasoline of low olefin content may be obtained by contacting an olefinic gasoline substantially free of lower boiling hydrocarbons with a catalyst comprising boron oxide on a refractory supporting material such as alumina, thoria, or ceria at proper operating conditions. We have founclthat when the proper preparation is by precipitating the alumina ina boric acid solution as follows: solutions of boric acid and A1C1s.6H2O are mixed together and N113 added until the pH reaches about 7. The mixture is then slurried and the excess water driven ofi 'by heating. The'Nl-hCl is driven oil by calcining.

The process of this invention is conducted at a temperatureof about 400 F. but below 650 F. and preferably within the range of 450 to 650 F. The pressures which are employed are such that at least a substantial portion of the material in atures in order to aid in maintaining a substantially liquid phase in the reaction zone. The space velocities which are employed are below about 15 operating conditions are employed the fraction of the product which boils within the range of the charging material will have a bromine number less than hall of that of the charging material withv the resultant increase of lead susceptibility.-

. In this manner the olefinic gasoline may be converted into a suitable aviation fuel.

It is, therefore, an object of our invention to produce a hydrocarbon traction boiling. in the gasoline range having a bromine number of less,v

the 1-0 octane number of the product with 4 ml.

of tetra-ethyl lead per gallon should'be in excess of and preferably in excess of 90. The 14; method is described in A. S. T. M. 614-411.

Catalysts which we have found to be especially suitable for this purpose comprise porous associations of boron oxide and oxides of metals such as aluminum, thorium and cerium. These catalysts may be prepared synthetically by various methods; for example in the preparation of a catalyst comprising boron oxide and alumina, the alumina may be in the form of pills or granules which are placed in a saturated solution of H330: and the excess water evaporated. Another method 0! and will ordinarily range from about 0.3 to 15 unit weights of charging oil treated per hour per unit weight of catalyst in the reaction zone. The preferred range is from about 0.5 to 5 units.

In the preferred operating range of this invention the amount of cracking, as measured by the accompanying gas formation, is negligible and, therefore, almost of the charge on the weight basis is recovered as a liquid. The amount of gas formation is negligible and the amount of catalyst deposit which is formed is also small when operating in the preferred range of temperature, pressure and space velocity. Onthe other hand, if temperatures are increased in excess of 650 F., cracking begins to take place, gas and catalyst deposit .are formed in increasing amounts and in general the operation is unsuitable for our purposes.

In one specific embodiment the present invention relates to a process for reducing the olefin content oif'an olefin containing fraction boiling in the gasoline range which comprises contacting said fraction with'a catalyst comprising boron oxide and a refractory metal oxide at a temperature of above 400 F., but below 650 F., without effecting substantial cracking and at a pressure such that a substantial portion of the hydrocarbon in the reaction zone is in the liquid phase to 'form a liquid product a substantial portion of which boils within the range of said olefin containing traction and has a bromine number of less than hall. that of said olefin containing fraction.

The charging stock which may be employed in this process may comprise any olefinic naphtha traction, gasoline or pure olefinic hydrocarbon boiling in the gasoline range. Ordinarily olefinic naphtha fractions or gasolines produced by cracking or reforming operations, preferably catalytic, will be employed since these charging materials are abundant andusually possess high I initial octane numbers.

. continuously passed through a bed of the granulai I catalyst maintained at reaction conditions. powdered catalyst is employed the catalyst may be suspended in the reactant stream and conducted through a turbulent reaction zone or through a vertical enlarged reaction zone'in which the catalyst is/maintained in turbulent motion by the upwardly rising reactants and conversion products.

The products from the reaction zone may be fractionated to separate a distillateof the desired end point from the bottoms. Any portion of the reaction products may, if desired, be returned to the reaction zone for further treatment.

Unlike other operations for producing aviation'base stocks from olefinic hydrocarbons, the catalyst may be used in this operation for a con siderable length of time without necessity for regeneration thereof. For example, times of processing may range up to about 75 hours more or less and a product having the necessary low bromine number will be continually obtainable. Normally times of processing longer than two hours are employed.

When regeneration is required it may be accomplished in situ by passing oxygen containing gas through the catalyst bed, or the catalyst may be removed to an external zone, regenerated by contact with an oxygen containing gas and returned to the processing zone for further use.

The following example illustrates the yields and quality of the aviation fuel stock which may be obtained when operating according to the process of our invention. In the following tests the charging material comprising a 280 F. E. P. gasoline was passed over three different materials, an alumina-boron oxidecatalyst containing approxin bromine number and lead susceptibility which is obtainable when employing the process 0'5? our invention.

We claim as our invention:

1'. A process for reducing the olefin content bon in the reaction zone is in the liquid phase,

imately 40% boron oxide, activated alumina, and i a composite of alumina-molybdena. The following data were obtained:

Charg- Acti- Alumina- Alumina- Catelyst ing vatod Molybboron stock alumina. dena oxide Temperature. F 527 534 830 Pressure pounds per s uare inch.; 800 800 300 We ght hourly space velocifty f1; 1.4 r 1. 5 2. 3

me o rocess g p hours 2 2 16 Product distribution:

Percent by weight of F., endpoint gasoline-.. 100 97 96 77.3 Percent by weight 1 of residue 280 F.. endpoint gasoline 3 4 22. 7 Bromine No 69 65 63 2s Octane numbe m1. tel/gel 88. 9 89 89. 2 96. 4

In the above test employing alumina-boron ox-= ide catalyst the gas produced wa negligible and the amount of catalyst deposit was very small, being less than *6 of 1% by weight based on the charge. a

The above tests clearly show the improvement to form a liquid product boiling substantially within the gasoline range and having a bromine number of less than half of that of said olefin containing fraction.

2. A process for reducing the olefin content of an olefin containing hydrocarbon fraction boiling in the gasoline range which comprises contacting said fraction with a catalyst comprising boron oxide on a refractory support, at a emperature of from about 400 F. to about 650 F and at a pressure such that a substantial portion of the hydrocarbon in the reaction zone is in the liquid phase, to form a liquid product boiling substantially within the gasoline range having bromine number of less than half of said olefin perature of from about 400 F. to about 650 F.

and at a pressure such that a substantial portion of the hydrocarbon in the reaction zone is in the liquid phase, to form a liquid product boiling substantially within the gasoline range and having a bromine number of less than half of said olefin containing fraction.

'4. A process for reducing the olefin content of an olefin containing gasoline which comprises contacting said gasoline with a catalyst contacting boron oxide, at a temperature of from about 400 F. to about 650 F. and ate pressure of from about 300 to about 1,000 pounds per square inch gage to maintain a substantial portion of the hydrocarbons in the reaction zone in the liquid phase, to form a liquid product boiling substantially within the gasoline range and having a bromine number of less than half that of said gasoline.

' an olefin containing gasoline which comprises contacting said gasoline with a catalyst comprising an association of boron oxide and alumina, at a temperature of from about 400 F. to about 650 F. and at a pressure of from about 300 to about 1,000 pounds per square inch gage. to form a liquid product boiling substantially within the gasoline range and having a bromine number of less than half that of said gasoline.

VLADIMLR HAENSEL. VLADIMIR IN. ITATIEFF. 

